1. Field of the Invention
The present invention is directed to a driving apparatus of a camera for transmitting driving force, through a gear train, to a cam ring which is threadedly engaged with a stationary barrel on the inside of the stationary barrel, wherein the stationary barrel is fixed to the camera body.
2. Description of Related Art
A zoom lens camera has been provided in which a cam ring is threadedly engaged (through helicoid gears) with a stationary barrel that is fixed to a camera body, with the cam ring being arranged on the interior of the stationary barrel. In the camera, a zooming operation is effected in a manner such that a plurality of lens groups are moved in an optical axis direction in a predetermined manner in accordance with the rotation of the cam ring. In such a camera, it is possible to provide an arrangement which associates a circumferential gear, provided on the outer peripheral surface of the cam ring, with a motor. In such an arrangement, a motor and gear train provided in the camera body are connected. A final gear of the gear train is connected to the circumferential gear. Accordingly, the cam ring can be driven by the motor through the circumferential gear.
In a camera having this type of mechanical structure for transmission of driving force, the final gear would be supported on the camera body side. Accordingly, it is unlikely that a prescribed distance between the rotational axes of the final gear and the circumferential gear will be unconditionally met upon attaching the stationary barrel to the camera body, due to limitations in the precision of the manufacturing process. In the case that an appropriate arrangement (i.e., alignment) between the final gear and the circumferential gear is not achieved, interaction between the gears would be incompliant, resulting in an undue burden on the motor and possible damage of the structure.